Alert archive / Georgia / Tornado Watches in 2020

Tornado Watch 498

October 10, 202021 counties in Alabama; 39 counties in Georgia

The Storm Prediction Center issued this tornado watch at Oct 10, 2020, 12:47 PM CDT for 21 counties in Alabama; 39 counties in Georgia. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Oct 10, 2020, 12:47 PM CDT (17:47 UTC)
Expired
Oct 10, 2020, 8:00 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Strongest gust expected
50 kt
All 60 counties

Barbour County, AL, Bullock County, AL, Calhoun County, AL, Chambers County, AL, Clay County, AL, Cleburne County, AL, Coffee County, AL, Coosa County, AL, Dale County, AL, Elmore County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Lee County, AL, Macon County, AL, Montgomery County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Talladega County, AL, Tallapoosa County, AL, Bibb County, GA, Butts County, GA, Carroll County, GA, Chattahoochee County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Crawford County, GA, DeKalb County, GA, Douglas County, GA, Fayette County, GA, Fulton County, GA, Gwinnett County, GA, Haralson County, GA, Harris County, GA, Heard County, GA, Henry County, GA, Lamar County, GA, Macon County, GA, Marion County, GA, Meriwether County, GA, Monroe County, GA, Muscogee County, GA, Newton County, GA, Paulding County, GA, Peach County, GA, Pike County, GA, Polk County, GA, Rockdale County, GA, Schley County, GA, Spalding County, GA, Stewart County, GA, Sumter County, GA, Talbot County, GA, Taylor County, GA, Troup County, GA, Upson County, GA, Walton County, GA, Webster County, GA

The radar

The Maxwell AFB radar (KMXX), 69 km from the middle of the area, began a volume at 17:49 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
50%
One or more EF2 to EF5 tornadoes
10%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
30%

Warnings issued inside it

21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Oct 10, 3:27 PM CDTTornado WarningFFCChattahoochee, Marion, Muscogee, Stewart27 min
Oct 10, 3:39 PM CDTTornado WarningFFCHarris, Muscogee51 min
Oct 10, 4:13 PM CDTTornado WarningFFCGwinnett, Walton32 min
Oct 10, 4:27 PM CDTTornado WarningFFCHarris, Meriwether, Pike, Talbot, Upson48 min
Oct 10, 4:38 PM CDTTornado WarningFFCCarroll, Heard37 min
Oct 10, 5:10 PM CDTTornado WarningFFCCarroll, Coweta, Fulton35 min
Oct 10, 5:11 PM CDTTornado WarningFFCTalbot, Taylor, Upson34 min
Oct 10, 5:21 PM CDTTornado WarningFFCPike, Spalding24 min
Oct 10, 5:33 PM CDTTornado WarningFFCCarroll, Coweta, Douglas, Fulton27 min
Oct 10, 5:44 PM CDTSevere Thunderstorm WarningFFCFloyd, Haralson, Polk31 min
Oct 10, 5:45 PM CDTTornado WarningFFCLamar, Monroe, Upson45 min
Oct 10, 5:49 PM CDTTornado WarningFFCClayton, Fayette, Henry, Spalding26 min
Oct 10, 5:55 PM CDTTornado WarningFFCFloyd, Polk35 min
Oct 10, 6:05 PM CDTTornado WarningFFCHenry, Spalding25 min
Oct 10, 6:17 PM CDTTornado WarningFFCClayton, Henry28 min
Oct 10, 6:24 PM CDTTornado WarningFFCButts, Henry, Lamar, Monroe36 min
Oct 10, 6:39 PM CDTTornado WarningFFCClayton, Henry22 min
Oct 10, 6:47 PM CDTTornado WarningFFCClayton, DeKalb, Henry28 min
Oct 10, 7:06 PM CDTTornado WarningFFCDeKalb24 min
Oct 10, 7:33 PM CDTTornado WarningFFCDeKalb, Gwinnett27 min
Oct 10, 7:55 PM CDTFlash Flood WarningFFCClayton, Cobb, DeKalb, Fulton6 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 5.8 hours before the alert went out and 84 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Peachtre/Fal Fld, GA at 12:00Z on 2020-10-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 261 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Peachtre/Fal Fld, GA at 12:00Z on 2020-10-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 166 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
261 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
503 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
166 m²/s²
0-3 km storm-relative helicity
217 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

736 
WWUS20 KWNS 101743
SEL8  
SPC WW 101743
ALZ000-GAZ000-110100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 498
NWS Storm Prediction Center Norman OK
1245 PM CDT Sat Oct 10 2020

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Much of eastern Alabama
  West central Georgia

* Effective this Saturday afternoon and evening from 1245 PM
  until 800 PM CDT.

* Primary threats include...
  A few tornadoes possible
  Isolated damaging wind gusts to 60 mph possible

SUMMARY...Scattered mini supercells are expected in a broken band
from eastern Alabama into west central Georgia through this evening,
to the east of the weakening remnants of tropical cyclone Delta. 
The storm environment will be sufficient for a few tornadoes, and
perhaps isolated strong/damaging gusts.

The tornado watch area is approximately along and 45 statute miles
east and west of a line from 45 miles northwest of Atlanta GA to 30
miles southwest of Dothan AL. For a complete depiction of the watch
see the associated watch outline update (WOUS64 KWNS WOU8).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 497...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0 inches. Extreme turbulence and surface wind
gusts to 50 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 20035.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 10, 2:23 AM CDTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Conecuh, Escambia, Marengo and 5 more2 hr
Oct 10, 4:00 AM CDTTornado WatchSPCBaldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 6 more10 hr
Oct 10, 7:09 AM CDTMesoscale DiscussionSPCBaldwin, Conecuh, Escambia, Monroe2 hr
Oct 10, 11:13 AM CDTMesoscale DiscussionSPCBarbour, Bullock, Chambers, Clay, Cleburne, Coffee and 14 more2 hr
Oct 10, 3:54 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Calhoun, Chambers, Clay, Cleburne and 12 more96 min
Oct 10, 6:17 PM CDTMesoscale DiscussionSPCBaldwin, Banks, Barrow, Bartow, Bibb, Bleckley and 51 more118 min

Nearby

Tornado Watches in Georgia, 2020Tornado Watches in Alabama, 2020Every tornado watch in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.